Microlensing-induced spectral variability in Q 2237+0305 |
| |
| Authors: | Lewis Irwin Hewett & Foltz |
| |
| Institution: | Institute of Astronomy, Madingley Road, Cambridge CB3 0HA,;Astronomy Group, Earth and Space Sciences, SUNY at Stony Brook, NY 11794, USA,;Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ,;MMT Observatory, University of Arizona, Tucson, AZ 85721, USA |
| |
| Abstract: | We present both photometry and spectra of the individual images of the quadruple gravitational lens system Q 2237+0305. Comparison of spectra obtained at two epochs, separated by ～3 yr, shows evidence for significant changes in the emission line-to-continuum ratio of the strong ultraviolet C IV λ1549, C III ] λ1909 and Mg II λ2798 lines. The short, ～1 day, light-travel time differences between the sight lines to the four individual quasar images rule out any explanation based on intrinsic variability of the source. The spectroscopic differences thus represent direct detection of microlensing-induced spectroscopic differences in a quasar. The observations allow constraints to be placed on the relative spatial scales in the nucleus of the quasar, with the ultraviolet continuum arising in a region of ?0.05 pc in extent, while the broad emission-line material is distributed on scales much greater than this. |
| |
| Keywords: | quasars: general quasars: individual: Q 2237+0305 gravitational lensing |
|
|
